In a conventional seven segment display such as those used on LCDs (Liquid Crystal Displays), the display wiring is routed without consideration for fault tolerance, and the icon (or pixel) selection matrix is typically generated to match the display. Such configuration allows for erroneous results to be displayed and could potentially result in patient mistreatment, for example, in the case where the seven segment display configurations are used in medical devices such as, but not limited to, glucose meters.
By way of an example, a glucose reading from a blood glucose meter used by diabetic patients that shows a value of 150 when in fact the actual measured value from the test strip using the glucose meter is 450 will inform the patient that they are in a good (clinically acceptable) range when in fact, the patient's condition requires immediate medical attention, for example. In addition, a failure of a decimal point in the displayed value may also erroneously inform the patient to take corrective actions that are either inaccurate (and thus potentially harmful), or to provide the patient with false positive values (those values are erroneous readings but are good values in the context of health treatment).
While some erroneous displayed values may be acceptable and thus not medically significant (such as, for example a glucose reading of 163 mg/dL which is erroneously displayed as 153 mg/dL), those other erroneous displayed values may potentially guide the patient to take corrective actions that are in fact therapeutically inappropriate (or alternatively, providing a false sense of accuracy, to guide the patient to take no action at all, when in fact, corrective medical action is necessary, as described above).
In view of the foregoing, it would be desirable to have an approach to provide fault tolerance in the display unit of an electronic device including medical devices such that failure modes of the electronic device display unit will show output values to the patient or the user of the electronic device that are either nonsensical, or clinically insignificant. In this manner, the failed display unit of the electronic device does not erroneously impact the patient decision based on the output display of the electronic device. Moreover, when a nonsensical value is displayed, the user of the electronic device such as a medical device will be aware that the device is malfunctioning, and will likely not continue its use.